The Problem With IIFYM

The new version of “going Paleo” has more than a few drawbacks.

A quick browse of fitness and wellness influencers on Instagram will show you that counting macros is the new “going Paleo.” In particular, the “If It Fits Your Macros” approach, also known as IIFYM, has gained a lot of traction over the past few years. The idea is that once you’ve figured out how many calories you need per day along with which portions of them should come come from protein, fat, and carbs, you can eat whatever you want—as long as you stay within your designated macros. It sounds simple enough, but nutrition experts have concerns about how appropriate this eating style actually is for athletes who are focused on performance.

“In general, IIFYM reduces food down to three components: protein, carbs, and fat,” explains Ryan D. Andrews, RD, writer for Precision Nutrition and author of A Guide to Plant-Based Eating. The problem is, this is an extremely narrow way to look at what you’re putting into your body. “To me, this is like reducing a person down to just three qualities. People are much more complex than just three qualities, as is food,” Andrews says. That’s because it isn’t just made up of protein, fat, and carbs.

“Food also offers countless other compounds that influence health,” Andrews says. Think: micronutrients like vitamins, minerals, polyphenols, and phytochemicals. You can easily meet your carb quota with powdered carbohydrates, points out Brandon Marcello, Ph.D., a nutrition expert who works with athletes to optimize performance, but that doesn’t mean you should. Similarly, living off of pizza, french fries, and protein powder isn’t going to cut it—even if you can achieve your macros with those options alone.

Why Food Quality Matters

You’ve heard the “a calorie is a calorie” argument and to some extent, it’s true: “All fats, proteins, and carbohydrates are metabolized the exact same way regardless of the quality,” says Marcello. That means whether you eat a piece of white bread or a banana, your body will process those carbohydrates with the same method. “The difference is with the speed in which they are metabolized, as well as the collateral benefits like micronutrients, which are needed for health and fighting disease.” Marcello additionally points out that some foods are pro-inflammatory while others are anti-inflammatory, which can also affect health and performance. “Your body might treat all foods the same way, but not all foods treat your body the same way,” he says.

“These meals have very similar macros, but are completely different on every other level,” Andrews says. One is packed with simple sugar and processed foods, while the other provides plenty of slow-burning complex carbs and plant-based protein. Meal 2 will provide fuel for a workout, whereas Meal 1 could result in a sugar spike and crash.

IIFYM also doesn’t take into account how different combinations of nutrients affect the body. “For example, eating a simple sugar by itself—such as candy—will likely send someone’s blood sugar levels skyrocketing, which can then set off a chain of other metabolic reactions,” says Victoria Lindsay Jarzabkowski, a Washington D.C.-based registered dietitian who specializes in sports nutrition. “But combine that with protein, fat, or fiber, and the effect on blood sugar is blunted.”

Macronutrient timing, which is crucial when performance is a priority, is also often ignored with this approach. “When it comes to fueling your workouts, there are times when you might want little to no fat or fiber, and specific ratios of carbs and protein,” Marcello explains. “Sometimes we want highly-refined and quickly-digestible foods, and at other times we want the opposite. How we fuel for recovery or post-workout is different than how we want to fuel pre-competition or pre-workout.”

Lastly, counting calories can lead to ignoring what your body’s needs. “When using IIFYM, you may not be in tune with your natural hunger and satiety cues, which is a huge mistake,” Jarzabkowski says. “People seem reticent to trust their bodies, but if you are mindful and connected to you physical state of being, your body can let you know when you need more fuel or when you’ve had enough.” In other words, if it’s 10 p.m. and you still have a bunch of macros left over but you’re not hungry, you shouldn’t have to consume those macros.

When Should You Use IIFYM?

Now, that’s not to say that there’s nothing good about IIFYM. Aside from being easy to follow, there’s another big plus: “One of the major benefits is the idea that all foods can fit into your diet,” says Jarzabkowski. For some people, that means a more balanced eating plan because they are able to work indulgent foods into their meals. People who have trouble implementing an 80/20 (or 90/10) lifestyle may find it easier to do within the confines of IIFYM. In this case, “those indulgent foods may be more enjoyable to eat, as they can be consumed guilt-free since you can make adjustments to the rest of your intake and still feel good about following your diet.”

Another time IIFYM can be appropriate is if you have a very specific aesthetic fitness goal like competing in a bodybuilding competition. “Combined with the right training method, IIFYM, when followed carefully, can result in added mass, reduced fat, and the desired aesthetic needed to win,” Jarzabkowski says.

But it’s important to realize that aesthetic fitness goals and performance goals don’t always require the same nutrition. “Just because you look a certain way on the outside doesn't mean that you're healthy on the inside. This means that it's important to consider both quality and quantity. Then, you can have the best of both worlds, and enjoy the occasional treat,” says Marcello.